Servicing a 1943 Rolex Bubbleback Calibre 645

by Eric GreenbergOctober 27, 2018

I recently fully serviced this beautiful 1943 Rolex Bubbleback. The Rolex bubbleback represents one of the earliest examples of Rolex’s Oyster case design elements, integrating a number of innovations aimed at increased water resistance. In addition, as an automatic watch manufactured in 1943, it is a very early example of automatic winding. It wasn’t until the 1950’s when automatic watches became more mainstream-- owning one in 1943 was a rarity. While very interesting and collectible, the Rolex Bubblebacks I have worked on and inspected have, on-average, lived hard lives. Marketed as active-lifestyle watches and some models having a few design eccentricities making them more difficult to service, their movements often bear the scars of past abuse and failed repair attempts. A prime example is the balance clock hairspring stud holding mechanism in calibre 645. It can only be described as brutal to the watchmaker, losing the majority of the painstaking hairspring adjustments made at the factory when the watchmaker does drops the balance off the cock to properly clean it. Getting it back-on and properly adjusted is painstaking and far more difficult than with other watches. As a result, you will sometimes see what almost appears to be vengeance taken to the watch by frustrated watchmakers. Parts are now often difficult or impossible to obtain and it can be cost prohibitive, relative to the value of the watch, for me to manufacture or perform major repairs to highly sensitive parts. You need to use your experience to drive optimization where and how you can in an imperfect environment. This particular watch went through a major transformation, despite its obstacles, rose to the occasion and is now running overall very nicely. It is once again an enjoyable watch and important part of history, ready to return to its owners wrist and perform its job once again.